Vacuum cleaner brush roll control device

ABSTRACT

A vacuum cleaner including a brush roll, a motion sensor assembly that detects motion of the vacuum cleaner and that generates signals indicative of the detected motion, and a brush roll control unit that controls operation of the brush roll based on the signals generated by the motion sensor assembly.

FIELD OF THE INVENTION

The present disclosure relates to vacuum cleaners and, moreparticularly, to a vacuum cleaner having a brush roll that isautomatically switched on and off during operation of the vacuumcleaner.

BACKGROUND OF THE INVENTION

Conventional vacuum cleaners typically include a brush roll disposed inthe vacuum cleaner nozzle head that rotates in contact with the surfaceto be cleaned to agitate and loosen ingrained dirt particles so that thedirt particles can be more easily sucked up by the vacuum. When a vacuumcleaner has a driven brush roll, such as a brush roll driven by a motoror an air forced brush roll, it is important for the user to constantlymove the nozzle head across a carpet. If the user holds the nozzle headstationary without lifting the nozzle head, raising the brush roll offthe carpet or turning off the brush roll, the spinning brush roll willapply excessive wear and tear on the carpet, as well as on the bristleson the brush roll, itself. This is particularly troublesome when theuser is distracted, such as when the user needs to pick up an objectthat is in the way of the vacuum, and walks away from the vacuum cleanerwhile the brush roll is still being driven in place.

There are known brush roll control devices that automatically shut offthe brush roll when the handle is disposed in the upright position.However, these control systems are not particularly effective, since theuser must remember to place the handle in the upright position when thenozzle head is held stationary to ensure that the brush roll isinactivated. Other systems use a switch that is activated to turn offthe brush roll when a vacuum wand is removed from the vacuum cleanerhousing for above-the-floor cleaning. However, when above-the-floorcleaning is not being performed, the user must once again remember toturn off the brush roll when the nozzle head is held stationary.Further, some vacuum cleaners simply do not allow the user to switch onand off the brush roll while the vacuum in being operated.

Accordingly, there is a need for a brush roll control system thatprevents the brush roll from spinning when the nozzle head is heldstationary, without the user having to perform a particular function,such as placing the vacuum cleaner handle in the upright position ormanipulating a switch that deactivates the brush roll.

SUMMARY OF THE INVENTION

A vacuum cleaner according to an exemplary embodiment of the presentinvention includes a brush roll, a motion sensor assembly that detectsmotion of the vacuum cleaner and that generates signals indicative ofthe detected motion, and a brush roll control unit that controlsoperation of the brush roll based on the signals generated by the motionsensor assembly.

In at least one embodiment, the vacuum cleaner includes at least onewheel disposed in contact with a surface to be cleaned, and the motionsensor assembly detects motion of the vacuum cleaner based on rotationof the at least one wheel.

In at least one embodiment, the motion sensor assembly includes aplurality of detectable indexes disposed around a circumference of theat least one wheel, and a sensor disposed adjacent to the at least onewheel, where the sensor generates the signals based on location of theplurality of magnetic elements relative to the sensor.

In at least one embodiment, the vacuum cleaner further includes a brushroll drive motor that drives the brush roll, and the control unitincludes circuitry that generates and sends control signals to the brushroll drive motor based on the signals generated by the motion sensorassembly to control operation of the brush roll.

A method of automatically controlling operation of a brush roll of avacuum cleaner according to an exemplary embodiment of the presentinvention includes sensing whether the vacuum cleaner is in motion usinga motion sensor assembly, stopping operation of the brush roll when thevacuum cleaner is sensed as being stationary, and starting ormaintaining operation of the brush roll when the vacuum cleaner issensed as being in motion.

In at least one embodiment, the method further includes delaying thestep of stopping operation of the brush roll for a predetermined periodof time after the vacuum cleaner is sensed as being stationary

These and other features of this invention are described in, or areapparent from, the following detailed description of various exemplaryembodiments of this invention.

BRIEF DESCRIPTION OF THE FIGURES

Various exemplary embodiments of the invention will be described indetail, with reference to the following figures, wherein:

FIG. 1 is a perspective view of a vacuum cleaner according to anexemplary embodiment of the present invention;

FIG. 2 is a detailed perspective view of the vacuum cleaner of FIG. 1showing internal components of the vacuum cleaner nozzle head; and

FIG. 3 is a circuit diagram of the control circuitry within the controldevice of the vacuum cleaner of FIG. 1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The various exemplary embodiment of the present invention are directedto a vacuum cleaner that includes a motion detector that is used toactivate and deactivate a brush roll disposed within the vacuum cleanernozzle head. When the vacuum is detected as being in motion, motiondetecting logic is used to keep the brush roll running or to initiallyactivate the brush roll. When the vacuum is detected as beingstationary, the motion detecting logic is used to deactivate the brushroll. Preferably, the deactivation of the brush roll is delayed for abrief period of time after the vacuum cleaner is detected to bestationary, and the activation of the brush roll is immediate aftermotion is detected. However, the present invention is not meant to belimited to this embodiment and, alternatively, motion control logic maybe used that results in any variation of delayed and immediateactivation and deactivation of the brush roll. Further, although theembodiment of the present invention disclosed herein is directed to anupright vacuum cleaner, it should be appreciated that the presentinvention is not meant to be limited to any particular vacuum cleanertype.

FIG. 1 shows a vacuum cleaner, generally designated by reference number1, according to an exemplary embodiment of the present invention. Thevacuum cleaner 1 includes a handle portion 10 attached to a vacuumcleaner nozzle head 20. The handle portion 10 may include a housing 12for storage of a vacuum hose 14, that can be removed from the housing 12and attached to a wand (not shown) for above-the-floor cleaning. Thehandle portion 10 may be pivotally attached to the nozzle head 20 sothat the handle portion 10 can be locked in an upright storage positionand unlocked and maneuverable relative to the nozzle head 20 when thevacuum is in use. The nozzle head 20 may include a pair of wheels 22,one on each side of the nozzle head 20.

FIG. 2 is an internal view showing various components held within thenozzle head 20. A brush roll 40 is disposed within the nozzle head 20.The brush roll 40 is driven by a brush roll drive motor 50 via a brushroll drive belt 48. The brush roll 40 preferably includes strips ofbristles 42 that assist in removing dirt from a carpet pile as the brushroll 40 is rotated by the brush roll drive motor 50.

A motion sensor assembly, generally designated by reference number 24,is disposed adjacent to one of the wheels 22. The motion sensor assembly24 includes a number of detectable indexes 26 disposed equally spacedaround the inner circumference of the wheel 22 and a stationary motiondetector 28 disposed adjacent to the wheel 22, so that the indexes 26are consecutively aligned in face-to-face relation to the motiondetector 28 as the wheel 22 rotates. The indexes 26 may be, for example,magnetic disks. The motion detector 28 is preferably a Hall-effectsensor element. In other embodiments of the invention, the motion sensorassembly 24 may include alternative sensor components, such as, forexample, a brush-contact switch, a magnetic reed switch, an opticalswitch, or a mechanical switch. Also, depending on the type of motiondetector used, the indexes 26 may be gaps, notches, or contacts, or theindexes 26 may be replaced with a single element, such as, for example,a cam lobe. In general, the present invention is not meant to be limitedto a particular type of motion detector assembly, and any known or laterdiscovered motion detector is suitable for use with the presentinvention.

The motion sensor assembly 24 is electrically connected to a controlunit 30. The control unit 30 receives signals from the motion sensorassembly 24, and based on the signals controls the operation of thebrush roll drive motor 50. As explained in further detail below, thecontrol unit 30 may include circuitry that controls the brush roll drivemotor 50 such that the brush roll 40 is driven by the drive motor 50when the vacuum wheels 22 are in motion and the brush roll 40 is notdriven by the drive motor 50 when the vacuum wheels 22 are stationary.

FIG. 3 shows the circuitry, generally designated by reference number 60,of the control unit 30 according to an exemplary embodiment of theinvention. The circuit 60 requires the motion detector 28 to pull low orshort to ground when a magnetic element 26 is detected. The motiondetector 28 is represented as a Hall-effect switch U1 in the circuit 60.In other embodiment of the invention, the Hall-effect switch U1 could bereplaced with a mechanical switch that repeatedly opens and closes acontact to ground (logic 0) as the wheel moves. The circuit 60 furtherincludes a discrete logic Exclusive OR (XOR) gate U2. An XOR gate hastwo inputs Pin 1 and Pin 2 and one output Pin 3. The output at Pin 3 istrue or logic 1 if both inputs at Pin 1 and Pin 2 are different, and isfalse or logic 0 when both inputs at Pin 1 and Pin 2 are the same(either both high or both low). A resistor R1 serves to provide a logic1 (+5 V) when the switch U1 is open. When the switch U1 is closed, alogic 0 (0 V) is provided. The logic output from the switch U1 is feddirectly to Pin 1 of the XOR gate, and also fed to Pin 2 of the XOR gatethrough resistor R2 with capacitor C1 going to ground.

Because it takes time for capacitor C1 to charge or discharge throughR2, the voltage on Pin 2 of the XOR gate is delayed for a fewmilliseconds. The previous logic state of the switch U1 is thus storedin capacitor C1 for a short period of time. Whenever the switch U1changes from high to low, Pin 1 of the XOR gate immediately goes low butPin 2 remains high and begins to go low as capacitor C1 dischargesthrough R2. For the short period of time when Pin 2 is high and Pin 1 islow, the output at Pin 3 of the XOR gate goes high briefly until Pin 2goes low. Similarly, if the switch U1 changes from low to high, Pin 1 ofthe XOR gate immediately goes high but Pin 2 remains low and begins togo high as capacitor C1 charges through R1 and R2. Again, for the shortperiod of time when Pin 2 is low and Pin 1 is high, the output at Pin 3of the XOR gate goes high but returns low as capacitor C1 charges andprovides logic 1 on Pin 2.

The output at Pin 3 of the XOR gate momentarily pulses from low to higheach time the switch U1 either opens or closes. The output of the XORgate could be used to reset a digital timer, or to reset a timingcircuit as shown in the right-hand portion of the circuit 60. Wheneverthe output of the XOR gate goes high, capacitor C2 is quickly charged upto about 4 volts through diode D1. Diode D1 only conducts when theoutput of the XOR gate is high but does not conduct if the capacitor ischarged and the output of the XOR gate is low. Resistor R3 serves todischarge capacitor C2 very slowly. For example, capacitor C2 maydischarge from 4 volts to 1 volt in about 2 seconds. Using a highercapacitance in C2 will provide a longer delay, so that 16 uF willprovide about 4.5 seconds to discharge and 50 uF would take over 14seconds to discharge. Comparator U3 has a reference voltage of +1 voltconnected to Pin 2. This reference voltage could come from a voltagedivider or other source. Whenever the voltage at Pin 3 of the comparatorU3 is higher than the voltage on Pin 2, the output at Pin 1 will go highsignaling to turn on the brush roll drive motor 50. If the voltage onPin 3 of the comparator U3 is less than the voltage on Pin 2 of U3, theoutput at Pin 3 of the comparator U3 will go low signaling to turn offthe brush roll drive motor 50. Resistor R3 and capacitor C2 form an RCtimer circuit. The status of the timer is the output of comparator U3which checks the charge voltage on capacitor C2. Thus, whenever thecharge on C2 is greater than 1 volt (the reference voltage) wheel motionwas detected recently and the brush roll drive motor 50 can remain on.If the charge on capacitor C2 is less than 1 volt, wheel motion was notdetected recently and the brush roll drive motor 50 should be turnedoff.

Alternatively, the XOR gate function or transitions from one logic stateto the other may be sensed using a microcontroller. The microcontrollercan check the logic state at the junction of R1 and R2 frequently and afree-running counting-timer can be reset each time the switch U1 changesfrom high to low or from low to high. If the timer reaches apredetermined terminal count (i.e. a predetermined-amount of time passeswithout any movement of the wheels 22), the brush roll drive motor 50 isturned off. The brush roll drive motor 50 may be turned on when thetimer is reset or has not reached the terminal count.

It should be appreciated that, in other embodiments of the presentinvention, the motor on/off signal does not need to directly control thebrush roll motor. Instead, the signal could merely be a control inputthat is combined with other signal inputs that indicate other conditionsthat may supersede the motor on/off signal. For example, a malfunction,such as a jammed roller or broken belt, may be detected, in which case asignal indicating the malfunction may be generated that supersedes anymotor on signal generated by the brush roll control device.

While the foregoing invention has been described in some detail forpurposes of clarity and understanding, it will be appreciated by oneskilled in the art from a reading of the disclosure that various changesin form and detail can be made without departing from the true scope ofthe invention in the appended claims.

1. A vacuum cleaner comprising: a brush roll; a motion sensor assemblythat detects motion of the vacuum cleaner and that generates signalsindicative of the detected motion; and a brush roll control unit thatcontrols operation of the brush roll based on the signals generated bythe motion sensor assembly.
 2. The vacuum cleaner of claim 1, furthercomprising at least one wheel disposed in contact with a surface to becleaned, the motion sensor assembly detecting motion of the vacuumcleaner based on rotation of the at least one wheel.
 3. The vacuumcleaner of claim 2, wherein the motion sensor assembly comprises: aplurality of detectable indexes disposed around a circumference of theat least one wheel; and a sensor disposed adjacent to the at least onewheel, the sensor generating the signals based on location of theplurality of magnetic elements relative to the sensor.
 4. The vacuumcleaner of claim 3, wherein the indexes are magnetic elements.
 5. Thevacuum cleaner of claim 4, wherein the sensor is a Hall-effect sensor.6. The vacuum cleaner of claim 1, wherein the vacuum cleaner furthercomprises a brush roll drive motor that drives the brush roll, and thecontrol unit comprises circuitry that generates and sends controlsignals to the brush roll drive motor based on the signals generated bythe motion sensor assembly to control operation of the brush roll.
 7. Amethod of automatically controlling operation of a brush roll of avacuum cleaner, comprising: sensing whether the vacuum cleaner is inmotion using a motion sensor assembly; stopping operation of the brushroll when the vacuum cleaner is sensed as being stationary; and startingor maintaining operation of the brush roll when the vacuum cleaner issensed as being in motion.
 8. The method of claim 7, wherein the vacuumcleaner further comprises a brush roll drive motor, and the step ofstopping operation of the brush roll comprises stopping operation of thebrush roll drive motor and the step of starting or maintaining operationof the brush roll comprises starting or maintaining operation of thebrush roll drive motor.
 9. The method of claim 7, further comprising:delaying the step of stopping operation of the brush roll for apredetermined period of time after the vacuum cleaner is sensed as beingstationary.
 10. The method of claim 7, further comprising: delaying thestep of starting the operation of the brush roll for a predeterminedperiod of time after the vacuum cleaner is sensed as being in motion.11. The method of claim 7, wherein the vacuum cleaner further comprisesat least one wheel disposed in contact with a surface to be cleaned, andthe step of sensing comprises determining whether the at least one wheelis in rotation.